Proper drainage is essential for keeping moisture away from the foundation of your home. If your drainage system is operating properly, water should not gather around or under your house. Often, drainage systems such as rain gutters stop next to the foundation and lead water off of the roof and onto the ground. This does very well in keeping most of your home dry, however, it can result in moisture seepage into your crawlspace or basement. If water is able to collect around the house or in the crawlspace it can cause damage to the stemwalls and/or foundation, or it can create the perfect environment for mold growth on exposed building materials.
There are all sorts of ways to channel water away from your home including gutter drains, modifying irrigation systems and landscapes, runoff drains, french drains, grading and more.